Washington: US Vice President Joe Biden dismissed the "malarkey" about efforts to reach a nuclear deal with Iran, and reassured Israel its security would not be put at risk.

"There's absolutely no daylight, none, between us and the Israelis on the question of Israel's security," Biden told the pro-Israel Saban forum in Washington.

"But as friends we have an obligation to speak honestly with one another. To talk about, not avoid the tactical disagreements we have."

Israel has publicly criticized US-led efforts to reach a deal to rein in Iran's suspect nuclear program, warning the administration of President Barack Obama is being fooled by the new, more moderate face of the Iranian leadership.

Relations have also become strained over failed efforts to try to reach an Israeli-Palestinian peace deal, amid private mud-slinging by both American and Israeli officials.

But Biden urged that such spats should not be allowed to overshadow relations.

"Let's not make more of what are normal disagreements between friends than warrants," Biden said.

And he insisted that "every aspect of" the Iran policy had been "discussed in detail" with Israel.

"There's been a lot of malarkey about our position on Iran. So let me state it absolutely clearly," Biden said.

"We will not let Iran acquire a nuclear weapon, period, period. End of discussion. It will not happen on our watch."

The global powers known as the P5+1 who are leading the efforts to stop Iran developing a nuclear weapon have extended their talks until June 30, after they failed to meet a November deadline for a deal.

"A diplomatic solution that puts significant and verifiable constraints on Iran's nuclear program represents the best and most sustainable chance to ensure that America, Israel, the entire Middle East will never be menaced by a nuclear-armed Iran," Biden insisted.

And he urged "please let's keep whatever disagreements we have in perspective, because... They don't go to the essence of who we are as Americans and who Israelis are."